The numerical simulation of dense gas-particle flows using Euler-Euler multi-fluid models requires robust algorithms capable of dealing with phase separation (absence of one or more phases from one part of the domain), strong phase momentum coupling, and to successfully enforce the particle packing limit. To achieve this goal, an iterative procedure for the solution of multi-fluid equations for gas–particle flows, with kinetic theory closures and frictional stress models for the description of the particle phase is presented and was implemented in the fully unstructured open source code OpenFOAM®. Improved interpolation practices have been adopted to ensure the smoothness of the solution in situations where the phase effective density presents steep gradients. Phase coupling was implemented using the partial elimination algorithm, which was incorporated in the improved interpolation practice. An implicit treatment for the particle pressure was implemented to ensure the robustness of the algorithm whenever the particle phase approaches the packed condition, where strong and rapidly changing stresses as a function of the dispersed phase volume fraction are present. Two example applications are presented in the animations below.
Fluidized bed with uniform gas feed.
Fluidized bed with a central jet.
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